Android画布中的倒数计时器

Question

I want to display a countdown timer while the user is in an activity. The activity is designed using a canvas.

So i used this code to display the timer in the activity.

private void drawTimer(){
        paint.setTextSize(10);
        paint.setTextAlign(Paint.Align.CENTER);

        new CountDownTimer(240000, 1000) {

            public void onTick(long millisUntilFinished) {
                int seconds = (int) ((millisUntilFinished/1000)%60);
                int minutes = (int) ((millisUntilFinished/1000)/60);

                String startTime =String.format("%02d:%02d",minutes,seconds);
                canvas1.drawText(startTime,
                        200, 400, paint);
                Log.d("ShowTimer",startTime);
            }

            public void onFinish() {
                canvas1.drawText("done!",
                        200, 400, paint);
                Log.d("ShowTimer","done!");
            }
        }.start();
    }

While in the log file its showing the countdown correctly. But in canvas its showing only 03:59, after that the value is not getting changed. Where is the problem if anyone can suggest the required changes. Thanks.

Changed it by using a TextView in the canvas dynamically -

layout = new LinearLayout(context1);
        textView = new TextView(context1);
        textView.setVisibility(View.VISIBLE);
        textView.setText("Hello world");
        layout.addView(textView);

        layout.measure(canvas.getWidth(), canvas.getHeight());
        layout.layout(0, 0, canvas.getWidth(), canvas.getHeight());
        layout.draw(canvas);

        new CountDownTimer(240000, 1000) {

            public void onTick(long millisUntilFinished) {
                int seconds = (int) ((millisUntilFinished/1000)%60);
                int minutes = (int) ((millisUntilFinished/1000)/60);

                String startTime =String.format("%02d:%02d",minutes,seconds);
                textView.setText(startTime);
                Log.d("ShowTimer",startTime);
            }

            public void onFinish() {
                textView.setText("done!");
                Log.d("ShowTimer","done!");
            }
        }.start();

Then also same issue, on loading the activity "Hello World" is displayed but timer is not getting displayed, but its showing in the log file.

Answer 1

public class CustomView extends View {

 Context context;
 String countValue="";

 public CustomView (Context context) {
    this(context, null);
    this.context=context;
 }

 public CustomView (Context context, AttributeSet attrs) {
    super(context, attrs);
    blackPaint.setColor(getResources().getColor(R.color.colorPrimary));
    this.context=context;
 }



 @Override
 protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    super.onSizeChanged(w, h, oldw, oldh);
 }

@Override
protected void onDraw(Canvas canvas) {
    canvas.drawColor(Color.WHITE);



    Paint paint = new Paint();
    paint.setColor(Color.BLACK);

    TextPaint textPaint = new TextPaint();
    textPaint.setColor(Color.BLACK);
    textPaint.setTextSize(46);
    textPaint.setTextAlign(Paint.Align.CENTER);
    float textHeight = textPaint.descent() - textPaint.ascent();
    float textOffset = (textHeight / 2) - textPaint.descent();

    RectF bounds = new RectF(0, 0, getWidth(), getHeight());

    canvas.drawText(countValue, bounds.centerX(), bounds.centerY() + textOffset+ 180, textPaint);

}

@Override
public boolean onTouchEvent(MotionEvent event) {

    return true;
}

public void CountDownTimer(final Canvas canvas){

    countDownTimer=new CountDownTimer(31000, 1000) {

        public void onTick(long millisUntilFinished) {
            countValue = millisUntilFinished / 1000+"";
            invalidate();
            Log.d("ShowTimer",millisUntilFinished / 1000+"");
        }

        public void onFinish() {

        }
    }.start();
}

}